(CNN) - Arizona Sen. Jon Kyl, a member of the Senate Finance Committee, has raised an objection to holding Treasury Secretary-designate Timothy Geithner's confirmation hearing Friday as planned, a spokesman for the senator tells CNN.

Kyl's objection comes a day after it was revealed Geithner had failed to pay necessary self-employment taxes while working for the IMF and continued to employ a housekeeper whose immigration status had expired.

(CNN) - President-elect Barack Obama's transition office defended Treasury Secretary-designee Tim Geithner Monday amid reports he failed to pay the correct amount of taxes for a period of time and employed a housekeeper whose work authorization had expired.

"The President-elect chose Tim Geithner to be his Treasury Secretary because he's the right person to help lead our economic recovery during these challenging times," Obama spokesman Robert Gibbs said in a statement. "He's dedicated his career to our country and served with honor, intelligence and distinction."

According the Wall Street Journal, Republican Sen. Chuck Grassley - the ranking Republican on the Senate Finance Committee - raised questions Tuesday about the status of a housekeeper who briefly worked for Geithner.

Geithner himself also reportedly didn't pay Social Security or Medicare taxes for "multiple years," according to the Wall Street Journal.

In his statement, Gibbs said Geithner made a "common mistake on his taxes, and was unaware that his part-time housekeeper's work authorization expired for the last three months of her employment.

"We hope that the Senate will confirm him with strong bipartisan support so that he can begin the important work of the country," Gibbs also said.

UPDATE: The Senate Finance Committee has released a document confirming Geithner failed to pay self employment taxes and employed a housekeeper whose authorization had expired.

According to the Obama transition team, transition officials discovered the problem on November 21, and notified the Senate Finance Committee soon after. The committee's release says members were informed of the problem on December 5.